Internal-combustion engine



Y `L. RAAB INTERNAL coMBUsTroN ENGINE June 19, 1928. 1,674,568

Filed March 51, 1926 RSheetS-Sheet l 3A? i /a June 19, 1928.

L. RAAB INTERNAL COMBUSTION ENGINE Filed March 31, 192e 2 sheets-sheet 2 //7 Ve Ufo/f.'

Patented .lune 1,9,

' UNITED .STATI-:s

.PATENT- omer..

v LnoroL'n man, or vmnngnus'rau.

mmnroonusrmn miam.

appagante mannen i 31, ieee, serial lo. 93,799, and in 'Auml April s, 192s.

This invention an internal-combustion .engine of ,the 4kind in which the scaven 'ligand charging of thecylinder are etlecte `by means `of air' supplied by afcomn pressor, and Ithe inven tion consists essentially inlprovidig means whereby the scavenging and charging are elfectedfroxn vseparate compression chambers in the .same com- 'pressor, the ylatterfbein'g provided with two ports which, are successively set into comy munication withthe Icylinders and which communicate; e. with different compression chambersat the time of induction.

By thisarrangement avery simple mechanism is obtained whereb an effective scavengin and a uniform c barging of all the cylin ers-will be achieved.

.Fig 1;.of., the accompanying f dravvm `represents an axial. section of a two-stro e engine having fourI radially arranged cy1in, ders which revolve about a stationary crank shaft, and

Figs. I2 3 and, are sectional vlewsof other, diiierenttypes of engines to whlch the invention is applicable.

Fig. 5 is a section across the compressor shown in'Fig.'1

-I1`i g 1;.6-is a sectional view taken` through one of the cylinders, and

Fig.Z 7,` a sectional view on an enlarged l scale of that part of the compressor Which contains the ports and the channel through which they communicate.

` In the construction according to Figs. v1 "andf 'to -7 `the engine is` enclosed in a casing v 2^v`vhich carries a stationary crank shaft 1. Four 'cilinders 7 are arranged radially about fa cran shaft by means of ball bearings and which .revolves together with the cylmders about casing 8 which is supported on the the crank. 4The connecting rods 4 of the pistonsv are associated with a ball-bearing -which turns aboutthe crank pin, one of the connecting rods being rigidly secured by meansof a bolt 5 to the ball-bearing so as to control the latter while the other rods are capable of angular displacement relative to the bearing. Connected to one side vof the casing 8 so as to rotate with vthe latter, is a' compressor casing 9 which encloses a compressor body mounted rigidly on the shaft '1. The compressor body is formed of two drumshaped elements 12 and 13 which are coaxial and which are eccentric relative to the shaft and to the casing 9 so that a crescent-shaped compression space is 9. The vanes are guided by the compressor.

body and reciprocated by the latter in the recesses 9. They are also controlled by a ring 15 to which they are connected by means of bolts 16 and forked arms. The v ring 15 is located between the drums 12 and 13 and supported on their adjacent bosses by means of a ball-bearing 14. Duets 17 carried obliquely through the heads of the vanes allow the air to pass in and out of the recesses 9. A flange 18 on the drum 12 forms a tight fit with the casing 9 and limits .the compression space at the engine side of the compressor. The flange is uniform and concentric with the compressor casing 9. The outer end of the compressor is closed by a plate 22 which rotates with the casing 9 which sup orts the end of the shaft 1 by means of a all-bearing. The plate 22 carries a shaft 23 whereby it is supported by .means of a ball-bearing in the end plate 24 of the casing 2, the shaft 23 being utilized for transmitting the motion of the engine to outside elements. The opposite end of the shaft 1 is hollow and contains the stem 33 of a funnel through which air is admitted into the crank chamber 8. The air admission is regulated by means of a throttle valve 34. From the crank chamber the air passes through apertures 35 in the chamber wall through perlpheral apertures 36 into the compression space. A channel 19 in the compressor drum 12 communicates, at one end of the compression s ace, with the different compression cham ers in succession. It also communicates with twspaced ports 20 and 21 which open through the flange 18 and which are 'normally closed by the adjacent -wall of the compressor casing 9. The induction and exhaust ports'of the cylinders are made in the cylinder sides so as to be controlled by the pistons 6. The induction port 11 is carried through the adjacent wall of the casing 9 so that while it is normally closed by the flange 18, it passes across admit the air from the compression chambers( kinto the" cylinder. vThe spacing ofy the ports and 21 yequals substantially that of the vanes so that one chamber' will.' be emptied through Kthefport 20 and the Vnext chamber tlirough the port 21.-v The port 21 supplies the `charging air and contains van atomiz-ing nozzle for` the vfuel which is admittedto VAthe nozzle through ducts 37 and 38 carried lthrough theshaft `1 and.

through thecompressor drum 12. The noz- --zle 40 is -surroundedfby alsleeve 44 through i and outside of `whichthe air passes. needle valve 42lcontrolled by al sleeve 41- l5 vand aspring 443, maintains i theatomizing nozzle 40y normally closed and opens under j the air-pressure. vThe duct 38 opens through m0' the nozzle 39 withoutl dismounting anyA otherl parts of the engine casing.

a nozzle 39 into" al space behind the nozzle. 40. This space opens through the periphery of the compressor drum 12 where it' 1s closedby a screw stopper 45. An aperture.

in the eriphery of the casing 9, normally `closed y a screw stopper 46, is arranged so as to pass across the stopper andallow -it'to be removed for cleaning and exchang- The exhaust ports 47 of the cylindersiaie situated farther` from the cylinder heads than the inductlon ports so as to be'opened later and closed before the latter by the istons. Theexhaust ports o en into shells 0 which are vconnected to t e compressor casing 9. r The tubular outlets 4of the shells are directed obli uely away from the rotating direction, and4 the orifices are cut aslant, as shown in Fig. 6, yso as to produce a'suction effect in the interior of thel shells. f The casing 2 receives the exhaust and discharges it at 25 through a funnel 26 formed in the lower part of the casin The. sparkin plugs $7* are screwed into the heads of t e cylinders, and the walls are depressed inwards'so as 'to form, around the lug and its sparking points, valleys wherein oil articles will be collected owing to the centrifugal .force and .burnt without contaminating the sparking points -'The casing 8 carries a pinion 29 which meshes with the.. driving wheel 30 of the ignition `apparatus 27 and also with the driv-- ing wheel 31 ofthe lighting dynamo 28. The wheel 31 has4 a cam wherebyet actuates a spring-supported plunger 50 lubricatingpurnp. f

The casing 2 has la detachabl ce The action is as follows l As seen in Fig. 5,- th 'cylindersandlthe compressor casing' revolve .inv anti-clockwise`l 4direction. Airis admitted to the'wiglest p0'1- r tion of the compression space'and is com pressed between the vanes as "itis conveyed by the latter to the narrow portion of the space; In each cylinder the cycle of operations is completed while the cylinder moves terasse once-'around the crankshaft. Considering the'piston movement in terms of angular cylinder displacement, the induction port is uncovered .by the piston. 70 before and closed after Vthe outer dead centre posi- .tion' of .the piston, while the exhaust port remains open 50 4at each side'of the same dead centre position. The induction port 1s also'controlled vbythe compressor drum 12 andv'remainsclo'sed until the piston hasv moved throughA 30" with .open exhaust port. Iny Fi justv a out to compressor, van pressor .isabout to enter into communication with the channel 19 for supplying scavengasslthe port 20 of the air 5, the port 11 of the' cylinder a is f the chamber?) of the coming air to the cylinder. The ports remaln in vcommunication during 45 lof the 'cylin-i l10 admission the exhaust port is closed and after another 20 the admission of fuel mixture ends by the -closing of the induction port by the compressor as Wellas by the piston. During the nextl110 of the cylinder dis-1 placement the admitted fuel mixture is compressed in the cylinder, and the next following power stroke extends over a. cylinder displacement of 130, i. e., untilthe exhaustV port is reopened.

ports 20 and 21 in succession, and slnce for each cylinder two compression chambers will discharge their air, as describedV in connec` tion with the chambers a and b, into the channel 19, it is evident that the same process will be repeated for each cylinder in succes` sion.' It is by allowing 90 cylinder displacement for the scavenging and charging of each cylinder, that the four cylinders are thus enabled to cooperate with the same compressor'ports. By keeping the scavenging air separate from-the charging air, the conipressor can be throttled down to a very small' supply'of fuel mixture for slow engine speed. If diiferent volumes of air should be rey quired for scavenging and -chargin the respectivevanes 17 may be arrange at4 different distances apart.

y The` invention is also applicable -to e11-` gines with vstationaryicylinder and rotating fioa Since all the cylinders pass the compressor ilo crank shaft, as shown in Figs. 2 to 4. In

the arrangement' accordingv to Fi 2, .the

compressor 1s arranged beside the cy inder orA cylinders and admits the air in theVA Y:seremosl s compressed by the lpiston 6 and returned to the compressor. As the latter thus receives @pre-compressed air it can be of ve small dimensions. The compressor 13is driven by the crank shaft.

- Fig. 3 shows an arrangement which operates in the same manner, the compressor being here situated between cylinders arranged at an angle relative to one another.

In connection with twin cylinders, such as shown in Fi 4, the compressor arrangement is particu arly advantageous as regards economic working. The operation is here the same as that described in connection with Fig. 2. Twin cylinders of this type may valso be used in the case of engines with revolving cylinders.

The compressor arrangement is also suit able for use in connection with four-stroke engines, it being driven from'the crank shaft at a transmission ratio of 1:2 or 1 to 4.

In the two-stroke en `ne, a reversal of movementmay be -broug t about by'an adl and means for supplying justment of the compressor body containing the channels.

Engines constructed according tothe invention will workfsatisfactorily with very heavy fuel.

I claim: l

l. In an internal-combustion engine a rotary air compressor having a crescent-shaped compression space, means for maintaining in said space a plurality of independent compression chambers, and means forscaveng- 1n and chargingl the engine with air from dierent alternate compression chambers.

2. In an internal-combustion engine having the features claimed in claim 1, a rotary air compressor having two outlet ports, .means for setting said ports successively into communication with the engine cylinders, air to said' ports from vdifferent compression chambers.

internal-combustion engine having cylinders, and means for settin the features claimed in claim 1 and wherein the compression chambers for scavenging and charging are of different dimensions.

4. In an internal-combustion engine having the features claimed in claim 1, a rotary air compressor having two outlet ports and a channel through which said ports communicate, means for setting said cessively in communication with t e engine the channel in communication with di erent compression chambers while different ports comvpen ent compression chambers, means for setting one of said chambers in communication with the induction port so as to suply scavenging air to the cylinder during the utter part of the outward stroke of the piston and during the commencement of the return stroke, and means for setting the next following compreion chamber in cornmunication with the induction port before the exhaust port is closed so as to supply chargIing air to the cylinder. A

6. he structure claimed in claim 5 and a crank casing communicating with the cylinders so as to form a pump space, said crank casing being in communication with the air compressor so that air is first sucked into the casing and then passed to the compressor.

7. An internal-combustion engine according to claim 5 having a stationary crank shaft and a revolving set of radially arranged cylinders, the movable com ressor elements being associated with said cy inders and the stationary elements with the shaft.

LEOPOLD RAAB. 

